Carburetor



June 6, 1933.

P. w. ENslGN .1,912,573

CARBURETOR Filed NCW.vv 25, 1930 l 5 Sheets-Sheet l /7 .W ff 4, E291. L] l as E I /a y if l? E Invefz/for Paz/l 52752.???

June 6, 1933.

v Filed Nov. 25, 19,30

P. w. lariqm CARBURETOR- 5 Sheets-Sheet 2 l'nz "paw, U 57252520,

Wfl/Zeg.

P. w. ENslGN l y 1,912,573

June 6, 1933.

CARBURETOR 5 Sheets-Sheet '3 Filed Nov. 25, 1930 Ewen (ar. Baza WT El? 549W P. W. ENSGN CARBURETOR Filed Nov. 25, 1930 Y Inl/622km".

PauLWfn June 6,. 1933.

bh/zeg June 6, 1933.

P. w. ENslGN 1,912,573

CARBURETOR Filed Nov. 25, 1930 5 Sheets-Sheet 5 fifa/772g Patented June 6, 1933 UNITED 'rari-:sii

PAUL 'W'. ENSIGN, OF SAN MABNO, CALIFRNIA, ASSIGNUR T0 ENSEGN IFlTJEtEWR G0. LTD., OF HUNTINGTON PARK, CALIFORNA, A CURPOMTON OF CALHURNI.

CARBURETOR .Application tiled. November 525, 1930. Hertel No. 493,046.

rllhis invention has to do with carburetors; and, among other objects, has for its object the production of a universal carburetor capable of producing most highly eflicient results for all types of engines and for all engine operating conditions.

It is well known in the art that carburetors, in order to operate with efficiency, must be designed and adapted to the particular job intended. A carburetor which operates with satisfaction on an engine of given size will not operate satisfactorily on another size, even though smaller. The carburetor adapted to an eight cylinder engine will not give satisfactory results, without redesigning, on a six cylinder engine. These things hold true even for slight differences in suction curves, manifold arrangements, and many other details-in which one engine may differ from another.

Afnd, when a carburetor is designed efficiently for a particular job, and used on that one only, it has been shown by experience necessary to provide in the carburetor numerous modifying arrangements, adapted to modify in various manners the many fuel*- and-air functions of the carburetor, in order to attain efliciency even on that single job.

A general object of this invention is the production of a carburetor which overcomes' these and other defects and shortcomings of previous carburetors; to provide a carburetor which need not be specially designed for various engines and which, although simple in construction and operation, produces re- Y sults of maximumieiiiciency. It is also an object to produce an efficiency greater in practical operation than that of any previous carburetor of which I am aware.

There are also various other objects, and the invention has corresponding,characteristics, as will be best understood from the following description. A major characteristic of the invention here described resides in its use of a metering venturi whose depression is utiburetors fuel is commonly drawn from the fuel supply by the'depression at the Venturi throat; but such carburetors commonly discharge the fuel into the Venturi throat where vaporization and expansion lof the fuel interferes ver substantially with accurate and efficient enturi action. A characteristic of my invention is that the fuel is metered by Venturi action Which is not obstructed or modified in any manner, and that ,the fuel so initially metered does not atl any time pass through that venturi on its way to the air stream. To prevent the flow of fuel to the metering venturi, provide in this carburetor a system of maintaining a differential depression between the venturi and the fuel nozzle or fuel vnozzle passage; so that the initially metered fuel is'carried on to the fuel nozzle and there, preferably in admiature with air, thrown into the main air stream.

rl`he differential fuel ,feeding depression just above referred to may be'and preferably -is of substantial amount, without interfering with the Venturi control of initial metering. rlhis substantial diHerential depression aids very materially in discharging fuel with such Violence into the main air stream that the fuel is thoroughlyand finely atomn ized.

And the arrangements for creating the differential depression also lend themselves most readily to a peculiarly efficient acceler" ating operation as will be hereinafter described. A characteristic of the accelerating operation is that, instead of causing the feed of additional accelerating fuel to lag behind the flow of increased air passing through the carburetor, my arrangement tends -to retard momentarily the increased flow of air and to accelerate the increased iow of fuel; which results in a most effective accelerating mixture.

The carburetor herein described also lends, itself very readily to the application of a simple idling system, as will be described; and, generally speaking, the invention prorequiring many of the small complications now found necessary in present carburetors. In order to set out my invention I shall A vides a carburetor of great simplicity, not K' lli characteristic of metering fuel by Venturi` depression is utilized; but in conjunction with afuel converting es well as carbureting device. insofar es there is common patents able subject matter between the two cases the hrcader common claims will be carrie in said prior application; leaving tothe present application the claims having to do with application ci the broader characteristics to carburetion, and the attendant-developments and improvements.

Figure 1 is a more or less diagrammatic view showing one form of my improved carburetor'. lin this view certain parts, as will be explained laters are for clarity or illustration and simplicity of description, shown in positions other ,than those actually occupied in the manufactured carburetor;

Fig. 2 is a detail section on line 2-2 "of/ Fig. l showing particularly the economizer Fig. 3 is a detail section showing a modification of certain 'arts as shown in Fig. 1;

Fig. 4 is a simi ar detail section showing other modifications of those same parts; i Fi 5 is a detail section of the same parts ofFig. 1 but showin the. structure as it has been made, whereas i 1 shows diagrammatic arrangement ci t e structure;

Fig. 6 is a detail section on line 6-\6 of. Fi 5;

1 sy? and 8 are detail sections showing certain parts of-Fig. 1 in other' operating positions, and showin 'the' idling valve mechanism of Fig. 9. ig. 1 shows the parts of the carburetor as operating wide open, Fig.

i 7 shows the parts in idling position, and

Fig. 8 shows the parts in an intermediate position;

Fi 9 is a sectional view similar to-Fig. 1 but s owing another form of carburetor as will be ex lained; f

10 is a detail section'taken as indicate by line 10-10 on Fig. 9;

\Fig. 11 is a view similar to Fig. 7, showing tly modified form of venturi; and l Fig. 12 is a view similar to Fig. 8 showing the modified4 form of Fig. 11.

Referring first to Figs. 1, 5 and 6 I show Leraars therein a suitable carburetor structure which includes a constant level fuel/chamber 10 in which the `liuel level is controlled b Hoet 1l and valve 12.y From this chamber uel Hows through passage 13 to orifice 1t 'located in the bottom of riser 15, which oriic'e is regulatably controlled in size by .needle valve 16 having an adjustin screw head 17 as illustrated. Riser 15 is set vertically in a well 18. The upper end of the riser has an en larged screw-threaded head 19 threaded into the upper end of the well, and the lower end of the tube has a conical tight fit at 20 with the lower conical endet the well. The upper surface of riser head 19 is cupped to form a small annular trough 19a, to camh any small .amount of fuel that might otherwise tend to run along chamber 22 and into the.V venturi; and to provide a concentration from which the fuel, is easily wi ed uI by the current of air passing up t roug suction tube 87.

Fuel which iiovvs upwardly through primary metering orifice 1t idowa upwar ly into riser 15 and also flows through orifice 18h into well 18. Withthe carburetor inactive, fuelstands at the same gravitational level in fuel chamber 1Q, well 18 and riser 15.

The riser 15 forms a passage through which fuel asses from the metering orifice 1t upward y to the depression chamber 22, into which the upper end'of the riser directly dischar es.' Depression chamber 22 has communication with the main suction assage of the carburetor, via passage 23 an ports 2t. The main suction passage has an air inlet 25, which may have a manual choke valve 26 if desired; a suction outlet 27 controlled by the 'usual throttle 28; and, intermediate the in..

let'and outlet, a Venturi passage 29 which is here shown as formed i a separate casting 30 .which also closes, or forms one iwall of, the annular suction passage 23 referred to. The ports 24' hereinbefore referred to eirtend through the wall of Venturi castin 30, communicating betweenA assage 23 an the Venturi passage substantially at its poignt oi? smallest cross-sectional area.

Suction applied to ports 24, and thus applied to depression chamber 22, is the operating suction which raises fuel through riser 15 and into chamber 22; there to be picked up and carried on by a suction applied to passa e 22 from main fuel nozfzle 35, as will short y be described. It may be 'noted et this point that the amount of suction or deis dependent on the air velocity through theI venturi, is substantially the sole factor in determining the amount of :fuel to be lifted to omiser system, do not negative the charac-` yIllipression applied to' suction ports 24, a'nd this i .y 15, as shown.

sage for fuel from the well to the riser; and

an orifice 181i feeds the well directly from tfuel passage 13.y The action of the carburetor on acceleration is so simple and positive that no further accelerating provisionsI are needed.

Another suction passage 36 communicates at one end with the calibrated fuel nozzle 35, and also communicates with depression chamber 22 hereinbefore described. The communication ishere shown as formed by a suction tube 37 ,coaxial with fuel riser 15, the suction tube'i37 also surrounding valve stem 16a, as does the riser 15. And this suction tube 37 preferably depends somewhat into depression chamber 22, as shown.

For purposes of providing an idling mixturecontrol in the form of device shown in Figures 1, 5 and 6, passage 36 is provided with a sliding control valve 40. In the actual construction 'this control valve uslides horizontally in va horizontal cylindric chamber.41. In Figure 1 this valve chamber is illustrated as vertical, in order that the complete operative parts of this form of the carburetor may be more nearly shown .in a single figure. Figures 5 and 6, however, show thc same parts in proper constructional relationship. .same or substantially so. Valve 40 has a redncedneck 40a, of smallerV diameter than that of suction passage 36, and'normally standing across the suction passage, so that normally the suction passage leading to fuel nozzle 35 is open to its widest extent. Valve 40' is pressed to this normal position by la small spring 42 of suitable strength. Valve 4() lits its valve chamber 4l rather loosely (for the inch and a quarter size of carburetor here illustrated a suitable looseness of fit is about 0.007 inch in diameter). An idling by-pass passage 44 communicates with valve chamber 41 beyond the end of valve 40, passage 44 communicating with suction outlet 27 at the suction or engine side of throttle 28. f

The high suction applied to passage 44 when throttle 28 is closed or nearly closed, ,auses valve 40 to move across suction passage 36 against the pressure of spring 42,A thus partially closing off suction passage 36.

The limit of valve movement toward closed position is fixed by the limiting stop pin45 The operation in both cases is the iting position is such that valve 40 does not quite close off suction passage 36. On opening the throttle, valve 40 goes back to its normal position, reaching that position typically at something less than half open position of the throttle. Operation of the parts to supply idling mixture will be described in setting out the whole carburetor action, hereinafter.

ocated in Venturi passage 29 is a control valve 50, mounted on a vertically sliding valve stem 51 whose lower end is provided with a dash piston 52 operating in dash cylinder 53 kept full of liquid by communication 54 with fuel chamber 10. Valve stem 5l slides in a tubular sleeve 51a whose upper end is above the fuel level; fuel rising around the valve stem lubricates it. rIhre dash piston is made up of a loose perforated disk 55 fioating between two stop danges 56 and 57 on valve stem 51, the lower flange 57 serving to close the disc perforations on the upward stroke. The downward stroke-set tling movement of valve 50 from the position of Figure 1 toward the position of Figure 7-is comparatively free and unchecked. rIhe dash pot action prevents control valve 50 from rising at high velocity under suddenly applied suction, and, together with inertia of the moving parts, makes the valve lag behind the increasing air velocity, so to speak. When throttle valve 28 is opened, even quickly, control valve 50 movesup at retarded velocity; reaching its position of equilibrium, for any given air velocity, after the air flow .has reached that velocity; and

`the valve has little or no tendency to move beyond, or oscillate around, its float-ing positionof equilibrium determined by the amount of suction being applied to it;

In the typical carburetor structure here being described, I have also incorporated a balance tube and an economizer. These elements, although having nothing substantial-v ly to do with the present invention, are necessary in'practiee in a successful carburetor, and will therefore be briefly described. The balance tube comprises a passage 60 communicating between air intake 25 and float chamber 10, to maintain a balance or fixed relationship between the pressure at the intake and that on the fuel in the float chamber.

The economizer system is shown as a passage 61 connecting with balance assage 60 of adjustment screw 43; and the typical liml Figure `4 shows a further' ino i communicating that port with the suction outlet 27 above the throttle. By such action, an increased depression from the suction outletk is placed upon port 62 and thus, through @l passages 61 and 60, on the fuel in the ioat chamber; suoli additional depression being moreor less suddenly applied as the throttle edge passes port 62 and then gradually disappearing as the throttle is open more wide- 3@ ly. 'llhe resulting temporary increased depression applied to the uel chamberV causes the thinning of the mixture when the car-V buretor' is acting at partial loads, but does not interfere with idling action or with full l E@ power1 operation when the throttle is wide open. Adjustable valve 63 is used to adjust the effective size of orifice 62.

'lhe economiser system herein described is the subject matter of xUnited States Letters 6@ Patent No. 1,799,585, issued Apr. 7, i931, to

. lll. Ensign, on Carburetors; the balance tube is the subject-matter of the 0. H. Ensign patent on Carburetor, No. 1,506,229, issued Aug. 26, 1924; andeither are, in themselves, claimed here.

Figure 3 shows modifications of certain parts ofthe idlingsystem shown in Figure l. Herehe idling bypass port `Maxis controllably bled through orifice 446 which communicates with the fuel chamber 10, orifice 446 being regulated by-valve 440. A. port ,44d leading from passage 44a, communicates 'with suction passage 36 to pvick up andicarry ofi fuel during idling operations.

dification, somewhat similar to that shown-in Fig. 3, except thatherethe port 4405 does not 'corny'J municate with suction passage 36 .but is extended on downwardly by the tube 44e into the fuel chamber 10, the lower end of tube 44e ha'ving a restricted orifice 44f at its lower end below the fuel level.-

Figures 5 and 'illustrate also the small choke valve 65 which may be placed across the depressionl chamber 22 and, manually operated, may be used either as a substitute for, or in conjunction with," choke valve26 at the air entrance.` Choking at either of these points causesa temporarily enriched 50Y mixture, as will be readily understood afterv consideration of the description of action which follows these descriptions of typical structures. l f l Figures 9 and lO'tshow another form of carburetor, similar in'it's action to the form shown in Figure 1, but whereinthe suction actuated valve 40 of Figure 1 is replaced by Va valve actuated mechanically from the throti t'le shaft. The valve in Figure 9 operates vertically and has a lower enlarged head 40g mounted on the lower end of a valve stem 40k. This valve plays vertically in arcylindric` bore '41a which crosses suction passage 36. The valve is normally pressed upwardly ,U5 by a spring 70, its upward limiting position being determined by a stop collar 71 bringing up against the adjustment screw 72, as shown in Fig. 10. Fig. 10 shows the parte in their idling positions, with the valve inv its adjustedl up ermost osition. Fig. 9 shows the parts in t eir ful open operating positions, with the valve in its lowermost position..

The upper endof valve stem l0/lJ has head 73 'adapted tol-cooperate with cam 74 on throttle shaft 28a. rl`he shape of this cain is such that, with the throttle in closed or idling position, the'valve is in its adjusted uppermost position, chokin od suction passage 36 to t e extent desire for idling operation (see Fig. 7). When the throttle is moved toward im position, cam 74 acts to press valve 40g ownwardly toward the osition shown in Fig. 9, reaching that position typically at Asomewhere around haii? open t rottle. An intermediate position is shown in Fig. 8. i

For purposes of more particularly describingrthese.t pical structures which have been found efficient in operation, l shall give typical dimensions of the more important operating passages, orifices, and other parts; it will be understood that l do this for the purpose oi enabling others to obtain a clear understanding of typical and illustrative einbodiments ot the invention, and not at all for the urposeof limiting the invention. 1 l believe t e invention to be ver much broader in its scope than the particu arand ty ical structuresherein described; the scope oi: the invention cannot be understood merely from sideration of; the characteristic modes of' operation hereinafter set forth. Those characteristic modes of opleration re uire, inthe particular structure ere descri ed, certain general relationships between various operating parts, and I shall indicate those relationshi s, as I have found them effective as applie to ,the/particular embodiments herein discussed.

The carburetor shown inthe accom anying drawings is of a size known as inc and a uarteig/ size. l

n a carburetor of the size mentioned, the diameter of the suction outlet is 111g. vThe diameter at the throat ofthe yventuri is 1195" and the diameter of the guide tube surrounding the valve stem central of the venturi is about {f1/r The annular passage area, around valve 5.0 when in its uppermost or wide open position, is the equivalent of substantially a 137s circle; so that fthe effective wide open area around lv-alve 50 is less than the effective area through the Venturi throat. c

Suction ports 24 at the throat of the venturi are six in number and of-drill size No. 27, diameter 0.1440 inch. The-interior effective area of suction .tube 37 equals the area of a 31;! inch bore. Theeffective' passage area through suction tube 37 is thereforeless thanl the total areas of suction ports 24. Suction lli passage 36 is ll inch in diameter. In Figure 9, the lower end of idling by-pass 44j, where it communicates with suction passage 36, isdrill size 50, 0/0700 inch diamter; its upper end, communicating With the suction outlet, is a No. 56 drill. Fuel nozzle 35, drill size No. 14 or 0.1820 inch diameter.

Bleeder opening 18a which leads from fuel chamber to well 18, is drill size No. 51; bleeder opening 15a through the upper end of riser 15 is drill size No. 53, orifice 21 at the lower end of the riser is drill size No. 53, and the auxiliary fuel feed orifice 186, which leads directly from the fuel chamber to well 13 is drill size No. 50.

rlhe weight of the control valve assembly (valve with its valve stem and dash pisn ton) is about 31/2 oz.; and the piston dish 55 has two holes of aboutY fr; inch diameter. rfhere is a slight clearance of the piston dislr in the dash cylinder, just enough to eliminate a tight fit and any friction.

@parution -rises and falls in accordance with the amount of air (air Velocity) passing through the carburetor. ./tt idling the control valve is either in or near its lowermost position, as shown in ll igure 7. lln this figure the valve is shown jiust above its lower position, slightly above the depression ports 2l. .tis the air velocity through the carburetor increases valve 5U rises higher, taking a position of equilibrium--fioating on the air stream, as it werefor any given air velocity; Figure 3 shows the position for approirima half power operation, while llig. 1 shows position for a full power operation.

lfhe weight of valve 50 and its connected parte, and the relative configurations of the venturi and valve are the main controlling factors in determining the equilibrium position of the valve for any given air velocity and in determining the difference between the depressions applied at the depression ports 2t and at the fuel nozzle 35. rela tive configuration suoli as shown in the draw* ings have been found to be very successful; and, with the valve of approximately the weight hereinbefore given, a difference of depression, fairly constant, of about (lt of an inch of mercury is maintained between the depressions applied at 2t and 35.

'fhe venturi, having at no time any fuel injected into it, becomes in practice exactly what it is in theory-an accurate metering instrument with a substantially straight line fuel metering function. The depression at the throat of the venturi or at depression ports 24.' is found in this carburetor to vary almost exactly as a constant function "of the air velocity. lConsequently, the depression applied in depression chamber 22 and applied to riser 15 to raise the yfuel is always an accurate function of the air Velocity; and this results 'in a certain definite proportion between the amount of air passing through the carburetor and the amount of fuel raised to the upper end of the riser. In other words, the initial metering of fuel is very accurately proportionate, to the amountof air, throughout the range of operation. And this is due to the fact that the metering venturi is not affected or obstructed in its operation by tlie` introduction of vany vaporizable or expansible duid to that venturi.

The fuel having been accurately metered, the next step in the operation of the carburetor is to move the fuel on into the main air passage without allowing it to dow into the Venturi throat and without passing it through the venturi on its way to the air passage. 'l`his, in general, is the function of the depression applied to nozzle 35 by the action of control valve 50. ll have stated that the control valve acts to apply a nearly constant additional depression at nozzle 35. "lhe important fact is that an additional depression is applied at nozzle 35. llt is not necessary that the difference in depressions be con'- stant; it is advantageous, however, that such difference be somewhere near constancy in order that during the normal operating range of the carburetor, the functions as herein described shall be uniformly carried out.

The relatively higher depression applied at nozzle 35 is applied, through suction pasn sage 33 and suction tube 3l', to chamber 22 directly over the fuel being lifted through riser 15; and the suction caused by lthe ladditional pressure piclrs up the fuel as fast as it reaches the top ofthe riser, and carries the fuel (with air) along through tube 3l( and passage 36 to nozzle 35, where it is thrown into the main air passage together with air and with a high violeiueev that insures rapid and complete atomization. ylfhis rapid and u forcible movement of the fuel into'the main air stream is due to the fact that there is a substantial depression difference between depression ports 2li and fuel nozzle 35..

scribed, and due to the differences in depression, as stated, air is, of course, constantly entering depression ports 2t, and flowing ywith the fuel up through passages 3'? and 33- to the nozzle. And, during the complete operation of the carburetor, throughout .its range, air always Hows outwardly from the Venturi throat through depression ports Qt. Neither air nor fuel ever flow inwardly through these ports into the venturi.

lin' spite of the fact that the higher depression at nozzle 35 is applied to depresu sion chamber 22, the depression in that chamber is controlled by the depression at ports 2t because. ports 2li act as a relatively wide open During the operation just previously detot lfd

until, when throttle 28 is closed down t0` j determined by the setting of stop pin 45. A

typical limiting position is one iii which valve closes passage 36 down to about one-third its normal cross sectional area.

In this last described position of valve 40 the suction applied to suction tube 37 from nozzle 35 is thus modified to draw up just the amount of fuel required for idling operation. During this idling operation it is the suction from nozzle 35 which predominates in suction chamber Q2, although that chamber is still bled by the depression ports 2f. The fuel drawn up and metered by the controlling suction thus applied to suction tube 37, is then taken on into the engine intake through idling passage lill, the depress sion in 44 being much lower than the controlled depression in suction passage 36;

v(Consequently the depression in passage la draws the metered fuel by the loosely fitting valve 40 and on through passage @Pinto the engine intake at the suction side. of tli'e throttle. Air for the idling mixture is, of course, being drawn through ports) 18a, 15a, and 24:, and to lsome extent through the venturi past control valve 50. i

iiiroin what has been said it can be understood how the Venturi depression is a controlling and practically the sole factor in metering fuel during normal carburetor operation and throughout the range; excepting only during idling operation and acceleration. During these last two mentioned operations the suction at nozzle 35 predominates and controls; but at no time does any fuel enterv the metering venturi. 'lhe fit of valve stem 5l in its bearing sleeve 51a is tight enough that the relatively thin volume of fuel would serve to lubricate the valve stein is either not drawn from the upper end of the bearing sleeve by suction or is drawn in such small amounts as not to vitiate ac.

curacy and efiiciency of operation.

For some installations it has been found unnecessary to provide the idling arrangements shown in Figures i or 9. For instance, as shown in lli'ig. 3, the idling passage 44a is adjustably bled at dat by air from the fuel chamber, thereby to modify thedepression in passage Ma when the throttle is closed; and the lateral passage 44rd picks up the fuel .from the nozzle passage 36. rlihis arrangement and the one shown in lfig.` 4E operate satisfactorily where then conditions are such that an excessive depression on nozzle 35 is not caused when the engine isridling.

Figure a shows a similar arrangement and one v'herein the depression of passage 44a ichs lup fuel dircctlv from float chamber 1Q. ts action will be understoorl readily without further description.

From what has now been described, the.

operation of the ,form shown i-n Figures 9 and 10 will be `largely understood without necessity of repetition. Here the valve 40g' is mechanically operated to perform the same depression throttling function as before described. The valve in Figure 9 operates ver'- tically; so that when it is in its uppermost position (Fig. 7) shutting off passage 36, the fuelflifted to passage 36lby the modified suction from fuel nozzle 35 is more or less held in passage 36 behind passage 40g; and the higher suction applied during idling through the idling passage 44j picks up the fuel directly from suction passage 36. Other wise the operation is the same as before described.

lt will be understood that neither the order in which vario-us forms of carburetors and modifications have been described, nor the extent of description applied to various {igures of the drawings, is to be taken as an indication of any fundamental preference. All of the forms here described have been found to have desirable features. On the whole, the form ofy lFig. 9 appears at present to give the most completely satisfactory operation uiider all circumstances.

Within limits prescribed by its size, thel carburetor which l have now described is universally applicable to any kind and size of engine Without the necessity of any material change in design or construction. lt is only necessary, when placing this carburetor on diderent engines, to set the three adjustments; it is not necessary to redesign the carburetor to suit any particular job 'lhe carburetor of a size suitable for a given size engine may be taken off and appliedto an engine of much smaller size and operate perfectly, sometimes Without even making further adjustments@ rfhis statement applies equally to engines of any number of cylinders and cylinder displacements, character of suction curve, manifold arrangements, etc.

ln applying the carburetor to any engine, it is only necessary for most efficient performance to make the three adjustments hereiiibefore described. Adjusting screw ll is set to control the wide open mixture; adjusting screw f3 is then set to control the idling mian ture; and then adjusting screw'63 is set to control the operation of the economizer.

After setting the economizer adjustment it may be desirable slightly to readjust the main'inixture setting. `When once adjusted, this carburetor has been found to produce very efficient results, both as to economy of operation and as to power. ,Both economy of operation and power results are largely due to the fuel metering functions as described; and the power production is very marked when an engine is operating wide open at low speed. find, furthermore, the carburetor, because of its peculiar and charlltltll lldti lift@ ASCS l@ located; so that the velocitycaused depression at the throat is ettained Without undue rictionel losses.

Upwardly Jfrom the throat the Wall curve starts iirst substantially straightup-the in?y E@ crease 1n area on upwardly progressing crosssections is :it first comparatively smell. ln,

Fig. 'l' this part oi the 'curve isfdesignsted Bin Fig. 7. ln llir. ll the corresponding part ol the curve is esignated lil. vln this latter ligure the curve Bl has e. iirst pert, immediately `above the throat, which is strictly vertical; in the design there shown the venturi is of constant diameter for shout three-sixteenths oil an inch meusured up- U Wards from the centers of ports 2li. f

Above the curve B or lil, the Wall curve of the venturi curves as at C increasingly outwardly-the area here on upwardly progressing` cross-sections increases en increasing rate-until the point ot greatest areajis nearly re'achechwvhen the curve re verses, as at l), to obtsin s smooth stream line dow around valve 50 when in its uppermost position.

ll have before mentioned the inet thot the cross-sectional dow eres. around volve 50, in its uppermost position, is somewhet less than the eres. nt the Venturi throat The outerV edge portions of the valve are conld; and the u per fece oil the vslve isconn cuvely curve as et rl`hese tvvo vulve curvatures form, with the reverse (conceve) curvature l) and the uppermost convex 45 curvature G of the airpussage, an upvverdly expandin annuler passage, around the valve, Wit 1 smoothly curved Walls end grud- `ual expunsion of urea to lead the fluids up to the cerburetor outlet with small frictional or eddy loss and at minimum de ression.

Actuel observations or" the uel end sir mixing notion taking place in the nir pas=` sage in the zone directly above the-valve, indicate that the high efficiency or the. corburetor results not only from eilicient metering and` economical proortioning oil the fuel, es shove described, ut also `from. the provision of n fuel and air mixing action of such efliciency as to ep roach, 1n the final w mixture taken into t e, engine complete atomization of the fuel. ln e. carburetorrspecially set up for test purposes, l have observed that by virtue of the illustrated' configurations given the air passage wallabove .5 the Venturi throat, and the valve itself, e

vexly curved, in verticel section, as shown etv nemers alongg7 the invvsrdlyfcurved Twell surface G,

end thet'heceuse oi the curvature or inward dei'lection oi this surface, the nir stream, or et leest n part oi air stream, is csused to .y radially inwardly 'from the upA er extent of this surface end to reverse its ilovv end pese downwardly :along the top curved surface of the vulve. Thus en inwardly end downwordly eddying llovv of nir is lished in the npvferdly diverging specs` between the top surffece of the valve end the surrounding fuel end uir pussnge Wall. ln order to explain cleerly the neture of the eddying.; air str in the divergent space shove the vulve, .l y state thut my oloservetions have indicated the ph sical condition ofi this eddy/ing rent oir nir to he similar to s smoke ring which the smolre particles are whirling udiully end dovvnvverdly invverd towery 1 l center of the ring. ildere the center of ring-shaped edd ing nir current is et redini center oi t e air passage, or the upper end portion oil the velve.

lln initiel division ntomizetion of the uel occurs by virtue of the high velocity discherge into the sir stresm lion/ing vvnrdly pest the vulve, of iuel und nir i 'n noznle 35, and due to this high velocity c cheres, the Jiuel from nozzle 35 is eilectively distributed in a horizontel direction entirely around the velve.` A second division and etomization of the iuel particles, and u sepsrstion Jiront the nal fuel mixture talren the engine, ol sny iiuel particles o apprecinble size, taires piece es the :zuel particles nre carried into the eddying and turbulent zone in the divergent space between volve surface l und the Wall surface (Gl. The sir turbulence set u in this zone has the eiiect of causingn the uel in the nel mixture to approach ideal complete atomization, by two notions. First, as soon es the tuel particles,

from nozzle 35 are carried into the turbulent air zone, 'otomization oi the particles trikes place due to their being subjectedto a more or less violent agitation in the air passage. Second, any articles ofappreciable size ere carried 4by t e eddyin air streem radially inward to the relative yquiescent and substantially less turbulent zone at the center ot the air passage directly above the valve cenare narrata/a ter, wherein such particles settle onto the down-sloping surface of the valve and then become swept into the downwardly eddying air stream and again subjected to atomization as they are picked up by the high velocity air stream flowing up past the valve. lt will .be seen that this last described operation is'essentially one of separation of the large particles yfrom small or atomized par ticles, an-d that this operation contributes to the forming of a hnal atomized' fuel and air mixture, in that it acts to move the undesirably large particles from the fuel that has been subjected to atomization `in the. mannersystated, and to permit only thosey particles in such fine state lof, division or atomizati on as to be capable of doatingfin the air stream, to pass out in the final fuel and air'mirture.

,For mostsuccessful results, the fuel nozzle preferably is placed in such position, relative to the valve, that when the valve is 'in its uppermost position, the center of the no'azle bore will be substantially opposite or slightly above the peripheral surface of the valve .at the point of maximum diameter.

A Satisfactory results may be had by arrangdll ing the valve and nozzle in the relative positions shown in llig. l. n

lt willthus be seen that the venturi, the air passage and the valve are so shaped as to perform their desired functions with minin mumlosses of pressure in the flowing air stream. Additionally, however, the configurations here described, perform another function which l note particularly. l have spoken of the fact thaton opening the throttle, retardation of upward valve movement causes a temporarily higher depression to be, applied tofeed fuel 'at a temporarily higher proportion: vDue to the fact that in.

the lower part of its-,upward travel the valve must move upwardly a greater distance, to increase the air stream cross-section by unit amount, than in the upper part of its travel; the valve action is thusv to temporarily give a relatively richer mixture when the throttle is quickly opened during ,low carburetor operation than during high carburetor operation. 'lhat is a desirable feature; among other things it promotes quick starting of a cool engine and highipower on quick aci celeration particularly at or from the lower ranges of operation. things, the functional diderence between Fig. 7 and llfig. ll will'be recognized. 'lhe actions just spoken ofare more pronounced in Figs. ll and l2., where the retarded valve has to rise a short distance before it begins at all to increase the air passage area. Thus, from the standing condition of Fig. l1, valve 50 rises substantially toward the position of Fig. 8 even for idling-it has to rise some-y what above the Vstraight Wall surface Bl in order to increase the area at all. Conse-r Considering these qlfently the design of Figf ll has all the characteristics of Fig. 7, plus an action tending temporarily to make a still richer mixture at idling or very low range. i

lt will be understoodthat where l l to applying pressure (or depression) from the air passage intake to the fuel chamber, l do notl mean to limit myself 4to the particular arrangement here illustrated and described. Such awbalance passage as l have l5 described is merely a means to compensate the whole carburetor action for any variations in intake pressure, such as are commonn ly due to altitude, the use of al dust strainer a wide open intake the pressure through the balance passage to the fuel chamber is practically atmospheric; and under those conditions the carburetor will function properly with the fuel chamber open to atmospherethat is, taking the pressure which is present at the mouth of the air intake.

@n the other hand, the carburetor here de- *Y scribed will function properly if the fuel chamber pressure be taken olf the air passage at some point where the pressure is less than that of the intalre; provided only that the other two pressures-that on the1 depression passage 22 and that on thefuel nozzlebe proportioned accordingly, so as to keep f5 the two pressure differentials., for metering vfuel and for hnally feeding fuel, in proper amounts and relation. Accordingly, the arrangements for applying the diderent depressions, as herein de- Mm j scribed, can be broadly considered as involving means for taking three different pressures or depressions off the air passage at diderent points in the passage, without any limitation on the particular places of pres- Mb sure take-off, or the methods or means of cre ating the differences in pressure. More particularly, however, l hud it of practical importance that the second pressure diderence (the diderential between depression passagelm E22 and nozzle 35) should be substantially uniform throughout the range of operation when the carburetor is. operating in equilib Y rium; but that during changes of operating speed this second pressure differential H5 should vary as l have described.

l claim: l. ln a carburetor having `an air passage p with a venturi, a fuel chamber, and a depression chamber in fuel communication with the n@ fuel chamber, the combination of means to apply pressure to the fuel chamber, means to apply a lower pressure from the throat of the venturi to the depression chamber, a fuel nozzle communicating with the depressiony chamber and discharging into the air passage at a point removed from the Venturi throat, g and means in the air passage to create at the fuel nozzle a pressure lower than that at the i Venturi throat,said last mentioned means in- 130.

refer 'mi 'or heating stove, etc., on the intake. `With w pression chamber in fuel communication with the fuel chamber; the combination of means to apply pressure to the fuel chamber, means to apply a lower pressure from the throat of the venturi to the depression' cham- \ber, a fuel nozzle' communicating with the .depression chamber and discharging into the air passage at 'a point removed fromvthe Venturi throat, and means in the air passage to create at the fuel nozzle a pressure lower thanl that at the Venturi throat, said last mentioned means including a valve floating on the air current in the venturi and adapted to be moved by the air current from a posivtion approximately closing the Venturi throat to a position vfurther along lthe venturi in the direction of air flow, the venturi having at its throat a portion of substantially uniform cross-sectional area extending in the direction of air flow, and then, extending further in the direction of air dow, having a flare whose cross-sectional area increases at anincreasing rate in said direction.

3. In acarburetor having an air passage with a venturi, a fuel chamber, and a depression chamber in fuel communication with the fuel chamber; the combination of means to f apply pressure to the fuel chamber, means to apply a lower pressure from the throat of the venturi to the depression chamber, a fuel L nozzle communicating with the' depression chamber and discharging into the air .passage at a pdint removed from the Venturi throat, and means in the air passage to create at the fuel-nozzle a pressure lower than that at the Venturi throat, said last mentioned means including a valve oating on the air current in the venturi and adapted to be moved by the s air current from a position approximately closing the Venturi throat to a position fur; ther along the venturi in the direction of air flow, the venturi having a flare, extending I from its throat in the direction of air iow, and the cross-sectional area of the `flare increasing at an increasing rate in said direction, and the valve fitting the venturi closely at the throat.

4. In a carburetor having an air passage with a venturi, a fuel chamber, and a depression chamber in fuel communication with the fuel chamber; the combination of means to apply pressure to the fuel chamber, means to apply a lower pressure from thethroat of the {ifenturi td the depression chamber, a fuel nozzle communicating with the depression chamber and discharging in to the air passage at a point removed from the Venturi throat, and means in the air passage to create at lthe fuel nozzle a pressure lower than that at the Venturi throat, said last mentioned means'including a valve floating on th air current in the venturi and adapted to be moved by the air current from a position approximateyly closing the Venturi lthroat to a position f tional area extending in the direction of airflow, and then, extending further in the direction of air flow, having a Hare whose crosssectionalarea increases at an increasing rate in said direction, and the valve fitting the venturi closely at the throat.

5. In a carburetor having an air passage with a venturi, a fuel chamber, and a depression chamber inI rfuel communication with the fuel chamber; the combination of means to apply ptressure to ythe fuel chamber, means to apply a lower pressure from the throat of the venturi to the depression chamber, a fuelnozzle communicating with the depression chamber and discharging into the air passage at a point removed from the Venturi throat, and means in the air pas- .sage to create at the fuel nozzle a pressure lower than that at the Venturi throat, said last mentionedv means including a valve floating on the air current in the venturi and adapted to be moved by the air current from a position approximately )closing the Venturi throat to a position further along the venturi in the direction of air How, the venturi having, extending from its throat, a iare whose cross-sectional area increases at an increasing rate in the direction of air flow, the valve having (a convexed outer yedge and a concaved stream-lined surface toward the outlet, and the air passage beyond the venturi having a stream-lined surface which, with the valve surface, defines an expanding passage for the owing air. i 6. lin a carburetor having an air passage `with a venturi and a throttle at the outlet side of the venturi, a fuel chamber, and a depression chamber in fuel communication with the fuel chamberythe combination of means to apply pressure to the fuel chamber, means to apply a lower pressure from the'Venturi throat to the depression chamber, a fuel nozzle communicating with the depression chamber and discharging into the air passage at a point removed from the Venturi throat, means in theuair passage to create at the fuel nozzle a pressure lower than that at the Venturi throat, an idling by-passage leading from a point in the air passage outlet beyond the throttle to the communication of the fuel nozzle with the HES depression4 chamber, and means actuated by virtue of throttle closure to close o saidVI tuel nozzle communicating with the depression chamber and discharging into the air lli passage at a point removed trom the Venturi throat, means in thea'ir passage to create at the tuel nozzle a pressure lower than that at the Venturi throat., an idling 4by-passage leadlrom a Vpoint/in the air passage outlet beyond the throttle to the communication ol the luel nozzle with the depression chamber, and means actuated by yirtue ot throttle closure to closeod said communication at a point between the nozzle and the luy-passage.

ln a carburetor haring an air passage with a yenturi and a throttle at the outlet side 'ol the renturi, a luel chamber, and a depression chamber in luel communication with the iuel chamber; the combination oi?l means to applypressure tothe tuel chamtlll ber, means to apply a lower pressure 'trom the Venturi throat to the depression chamn bar, luel nozzle communicatingri,n with. the depression chamber and discharging Ainto the air passage at a point removed trom llt the Venturi throat, means in the air passage to create at Vthe iluel nozzle a pressure lower than that yat the Venturi throat-an idling bypassage leading trom a point in the air passage outlet beyond the throttle to the communication oit .the luel nozzle., with the depression chamber, a yalre controlling the communication ol the tual nozzle with the K depression chamber and located in the com? any,

lid'

munication between the luel nozzle and the y-passage, and mechanicalmeans lor actuating said ralre upon opening and closing moi/ement or the throttle.x

, t, ln a carburetor having an air passage with a Venturi andv a throttle at the outlet side ol the Venturi, a luel chamber, and a depression chamber in luci communication rvith the luel chamber; the combination ol means to apply pressure to the fuel chamber, means to apply a lower pressure trom the Venturi throat to the depression chamber, a ituel nozzle communicating with the depression chamber and dischargin Ainto the air passage at a point removed rom the Venturi throat, means in the air passage to crepassage leading from a point in the air` passage outlet beyond the throttle to the communication lofi the fuel nozzlewith the 65,depression chamber, a valve controlling the commuiiication ot the fuel nozzle with, thev depression chamber, andineans whereby olel pression at the outlet side ot the throttle causes Vactuation ol said valve.

l0. ln a carburetor, an air passage having anintalre and an outlet with an intermediate venturi and a throttle between the venturi and" the outlet, the Venturi haring at its inlet side a stream-lined constriction leading to its' throat and at its outlet side leading trom its throat atlarc Whose cross-sectional area increases at an increasing rate toward the outlet, a luel chamber, a depression chamber in.

suction communication with the venturi at its throat, a fuel riser leading trom the luel chamber to the depression chamber, a 'fuel nozzle discharging into the air passage at a point beyond the Venturi ilare, a passage connecting the tuel nozzle and the depression chamber and including a riser entering the depression chamber directly over the aiorementioned incl riser, and a Valve iloating on the air stream in the airpassage and movable lrom a position substantially closing the Venturi throat to a position toward the outlet.7

lill

lili

lill

ll. ln a carburetor, an air passage haring an intuire and an outlet with an intermediate 'venturi and a throttle between the renturi and the outlet, the venturi haringv at its inlet sideva stream-lined constriction leading to its throat and at its outlet side leading trom its throat a ilare Whose cross-sectional area increases atan increasing rate toward the outlet, a `luel chamber, a depression chamber in suction communication "with the Venturi at its throat, .a iuel riser leadingrlirom the 'luel Vitt lllll chamber to the depression chamber, :tuel

nozzle discharging into the air passage at a point beyond the Venturi llare, a passage conl necting the fuel nozzle and thei depression chamber and including a riser entering the vdepression chamber directly over the attorementioned iuel riser, a rallye doating on vthe 'air stream in the air passage and moi/able Jfrom a position substantially closing the Venlud lll@

turi throat to a position` toward the outlet,

turi at its throat, a luel riser leading trom lili lZll

the luel chamber to the depression chamber,

a luel nozzle discharging into the air pasf sage at a point beyond the Venturi hare, a passage connecting the luel nozzle and the depression chamber and including a riser entering the depression chamber directly over the aforementioned fuel riser, and a valve 4floating on the air stream in the air passage and movable from a position substantially closing the Venturi throat to a position toward the outlet, the valve having a convened` outer edge and a concaved stream-line surface toward the outlet, andthe air passage beyond the venturi having a stream-lined surface which, with the valve surface, denes an expanding passage for the flowing air.

13. In a carburetor having a fuel chamber, an air passage with a venturi, and a fuel nozzle discharging into thel air passage at a pointfremoved from the Venturi throati/ a depression chamber in communication with the Venturi throat to take a depression therefrom, a fuel riser leading from the fuel chamber into the'depression chamber, another riser leading out of the depression chamber from a point directly7 over the fuel riser and con# necting with the fuel nozzle, and means in the air passage to establish on the 'fuel nozzle a depression greater than that at the Venturi throat. e i

14. In a carburetor having a fuel chamber, an air passa with a venturi, and a fuel nozzle discharging into the air passage at a point Aremoved from the Venturi throat; a

depression chamber in communication with.

the Venturi throat to take a depressiontherefrom, a fuel riser leading from the fuel chamber into the depression chamber, anotherl riser leading out of the depression chamber from a point directly over the fuel riser and connecting with the fuel nozzle, and means in the air passage to establish on the fuel nozzle a depression greater than that at the Venturi throat, Asaid y:means acting to maintain a substantially uni orm dierence in depression throughout the range of carburetor operation l and varying/air'I velocities through the air' passage. g o a 15. In a carburetor, the combination comprising, walls forming an air passage having l Aa valve doating on the air current in said passage and positioned Within said annular concave wall thereof, said valve being adapted to be moved by the air current from 7aA venturi, and an outlet beyond the venturi,

said passage having an annular concave wall, fone portion of which is formed by a lare in said venturi, extending` from the Venturi.

'l the venturi in the direction of air-flow, walls forming an annular depression chamber surroundingthe venturi, a plurality of vcircularly spaced openings leading from said chamber into the throat of the venturi, ieans for supplying fuel to 'said depression chamber, and means for delivering fuel from the depression chamber to the air passa e at a point beyond the throat of the venturl in the direction of air flow.

In witness that I claim the foregoing I have hereto subscribed my name this 20th day of November 1930.

PAUL W. ENSIGN.

a position close to` the Venturi throat to a position further along the venturi in the direction of air How, and the valve having a convexed outer edge and a stream-lined surface toward the outlet, a fuel chamber and means for delivering fuel from said c amber to the air passage at a point beyond the throat of the venturi in the direction of air flow. Y

16. In a carburetor, the combination comprising, walls forming an air passage having 

